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Discussion Starter · #1 ·
Hey i have a 2004 raptor 660. It has a white bros series e exhaust, k&n air and a jet kit. Just recently i put in a stock diameter piston that raises the compresion to 11:1, i also put a stage one hotcam in it, and i have been running a 50:50 mix of vp110 and 91 pump gas. After i got that all done it would run but it needs jetting bad. My mechanic says the carb isn't big enought. What jets do i need to change and what size if you know, or just tell me what i need to do? There are dead spots in the throttle and it backfires horribly when wide open.
 

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Discussion Starter · #3 ·
The more opinions the bdtter i would like as much advice as possible, so everyone tell me what you think. Just a note without this thing being jetted it will finally spank a souped up ltz 400 i cant wait till it runs at its fullest.
 

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the stock carbs are plenty to feed that motor.

what jets are in it now?

I'd recommend you buy yourself a GYT-R jet kit, it has the 25 pilots which you will need, new needles and mains up to 165 which is where you'll probably end up.

your final jetting should be close to 25 pilots 2&1/2 turns out on screws, gyt-r needles on 4th clip and 160/165 mains. That should get you in the ball-park anyway.
 

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vp110/91 mix ?? You doing that for fear of detonation or more hp?? I'm not sure with the mods you have that it will do much in favor of hp.
 

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Discussion Starter · #6 ·
Hey i do mostly racing on highways and make trips to the dunes in oklahoma. As for the vp it does add alot of hp and i use it for the detonation problem, since with 91 octane fuel all that is is prolly just a higher research #. If anyone else has a similar setup let me know your elevation fuel and jet settings, and that will be cool.
 

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An 11:1 piston with stage1 cam you should be good for just regular 92 and up octane, but I know what your saying about the actual octane thats being put in your tank, here in ohio-we've had countless cases where they test the higher octane pump gas and its actually 87 octane the gas company puts in them to make more money off the same lower performance gas. Ohio also gets the $hitiest refined gas as well because were less concerned about air pollution up here for some reason. Its bull$hit, but it happens, better to be safer...
The vp fuel tends to make more hp on higher modified motors, but does make hp on the lower modified ones.
 
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